Woodward ProAct I, Product Manual

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ProAct I/II Manual 04121
12 Woodward
Chapter 2.
Description of Operation
General
This chapter provides an overview of the features and operation of the ProAct™
Digital Speed Control and Actuator system. Figure 1-4 shows the actuator
outline. Figure 1-5 is the wiring diagram for reference in the following
descriptions. Figure 1-3 is a schematic cutaway view of the ProAct II actuator.
The ProAct Digital Speed Control uses a 16-bit microprocessor for all control
functions, such as computing engine speed, performing the control algorithm
calculations, speed ramps, etc. All control adjustments are made with a hand
held terminal/display (see Figure 4-1) that communicates with the control via a
serial port. The terminal/display is disconnected from the control when not in
service to provide security against tampering.
The operating program is adjusted through seven menus accessed through the
hand held terminal display. Details of these seven menus are contained in
Chapter 4 of this manual.
The speed sensor contains a special tracking filter, designed for reciprocating
engines, which minimizes the effects of engine torsionals or irregularities in the
gear used for sensing speed. This provides exceptionally smooth steady-state
control and allows the control dynamics to be matched to the engine.
The speed signal itself is usually provided by a magnetic pickup supplying an AC
signal from 1 to 60 Vrms to the control. The frequency (in Hz) is proportional to
engine rpm.
The control features exceptional spike, ripple, and EMI (electromagnetic
interference) rejection. Discrete inputs are optically isolated and capable of
rejecting EMI and variable resistances in switch or relay contacts. Analog inputs
are differential-type with extra filtering for common-mode noise rejection. This
protects the control from spurious interference and noise which can cause speed
and load shifts. The chassis should be bolted to a good ground to ensure
effective EMI/RFI protection.
An auxiliary ±2.5 volt input is provided to interface with Woodward Load Sensors,
to provide isochronous load-sharing operation.
Control Dynamics
The algorithms used in the ProAct control are designed specifically for
reciprocating engine applications. Control dynamics vary automatically as
functions of both speed and actuator position to provide better performance over
the entire engine operating range.